[Mrsevic]

@knc1 Thank you for your amazing response. You and your cynicism helped me a lot.

I never use any synchronization. I keep all of my content in cloud(onedrive) and Calibre. I disabled it on amazon page and in seting. All the time I keep airplane mode on for battery.

I though that by reseting device all partitions with jailbreak are automaticly deleted. I was obviously wrong.

@shaman Man, thank you a lot. I'll probably downgrade it today.

Nevertheless, it turns out device was slowed down due to enourmous heat in my room. I just took device this morning and everything is normal but still little slowed than previous state.

Calibre conversion is good, when I search for some strange words everything seems normal.